Re: Sealing ductwork - mastic or foil tape???
With little experience with either, my gut instinct is that mastic would last longer. Though the foil tape designed for ducts is superior to other tapes, I would be afraid of the adhesive drying out eventually causing the tape to peel off. The mastic seems like it would maintain its bond with the ductwork.
Of course, I could be wrong.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.